Niger meningitis outbreak: All districts are now below the epidemic threshold

The World Health Organization (WHO) announced Wednesday that between 1 January and 28 June 2015, the Ministry of Public Health of Niger notified WHO of 8,500 suspected cases of meningococcal meningitis, including 573 deaths. This was the largest meningitis outbreak caused by Neisseria meningitides serogroup C in the African meningitis belt.

African meningitis Belt/CDC

The number of suspected cases increased very rapidly, tripling weekly between 1 and 15 May. Thirteen districts in Niger crossed the epidemic threshold. The five districts of Niamey, Niger’s capital and largest city, reported 5,267 suspected cases and 260 deaths.

The outbreak peaked between 4 and 10 May when 2,182 cases, including 132 deaths, were reported. Since then, the outbreak declined substantially – from 22 to 28 June, a total of 11 cases, including 2 deaths, were reported.

Laboratory tests confirmed the predominance of Neisseria meningitidis (Nm) serogroup C in the affected areas, with Nm serogroup W also being identified in 12% of positive samples. Although serogroup C has been the predominant cause of meningitis in wealthy countries, it has never been of high concern in Africa.

Together with its partners, WHO assisted the government of Niger in the implementation of mass vaccination campaigns and other emergency control measures.

In addition to mass immunization campaigns and enhanced surveillance, social mobilization and case management activities were performed in all affected areas. These measures led to the control of the outbreak. Currently, all districts are below the epidemic threshold.